<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <script crossorigin src="https://unpkg.zhimg.com/react@17/umd/react.production.min.js"></script>
  <script crossorigin src="https://unpkg.zhimg.com/react-dom@17/umd/react-dom.production.min.js"></script>
  <title>demo2</title>
</head>

<body>
  <div id="root"></div>
  <script>
    const rootElement = document.getElementById("root");
    const ele = React.createElement('div', {
      children: 'Hello world',
      className: "Hello",
      id: 'demo2'
    });
    ReactDOM.render(ele, rootElement);
  </script>
</body>

</html>